TRAVERSE CITY, Mich.  After fighting the federal government for more than 18 years, Keith Carabell is resigned to more uncertainty after the U.S. Supreme Court ordered another look at his plan to build condominiums in a wetland area.

In a case so divisive it produced five separate opinions totaling more than 100 pages and no clear majority, the court ruled that the government can block development on hundreds of millions of acres of wetlands, even on land miles away from waterways, as long as regulators prove a significant connection to the waterways.

The 5-4 decision sends Carabell and another Michigan developer's cases back to a federal appeals court -- with no end to the spat in sight.

"I'm not sure I'll live to see the end of this," the 79-year-old accountant said.

In his first major environmental case, Chief Justice John Roberts came up one vote short of dramatically limiting the scope of the landmark Clean Water Act. But at the same time, property rights advocates won a new test for when wetlands can be regulated. Moderate Justice Anthony M. Kennedy said there must be a "significant nexus" between the wetland and a navigable waterway.

"It muddied already muddy waters on this issue," said Jim Murphy, wetlands counsel with the National Wildlife Federation.

The court's four conservative justices favored sharply curtailing the government's jurisdiction over wetlands under the 1972 Clean Water Act, while the four liberal members argued the U.S. Army Corps of Engineers should have discretion to protect wetlands adjacent to tributaries of waterways such as rivers and lakes.

Roberts and the court's other three conservatives complained in an opinion that virtually any land in America would be covered under the government's interpretation of the law.

But the controlling vote was cast by moderate Justice Anthony M. Kennedy. He joined the conservatives in overturning lower court rulings against Carabell and developer John Rapanos, yet said wetlands could come under the Clean Water Act if they "significantly affect the chemical, physical and biological integrity" of nearby navigable waters.

"It's really a bizarre situation," said Richard Lazarus, a Georgetown University law professor.

It was a dramatic conclusion to a pair of property rights cases the justices agreed to review last fall, just days after Roberts joined the court. The Bush administration defended the law and had urged the court to stay out of the case.

The justices themselves appeared troubled by their inability to agree on a clear standard for wetland protection. Roberts said the result was confusing and that "lower courts and regulated entities will now have to feel their way on a case-by-case basis."

Stevens predicted developers would be uncertain about whether they would need permits to work around wetlands and regulators would struggle to apply Kennedy's test for determining whether land is connected to a navigable waterway.

Several justices urged the U.S. Army Corps of Engineers, the agency that determines whether to allow development of federally regulated wetlands, to clarify its regulations.

"I think it's a message to all federal agencies that they need to define their authority clearly under the law," said Reed Hopper, a lawyer with the Pacific Legal Foundation, which represents Rapanos.

Congress also may get involved. Bills pending in the House and Senate favor an expansive view of federal authority over wetlands.

Rapanos, 70, of Midland, ran afoul of regulators by attempting to develop three parcels they said contained wetlands.

He filled in a portion of one property with sand to build a shopping center, defying cease-and-desist orders and insisting it had no wetlands. The nearest navigable waterway is a Lake Huron tributary river about 20 miles away, but state and federal officials said adjacent ditches provided a direct surface link.

Carabell wanted to build condominiums on a 19-acre parcel in Macomb County, north of Detroit. He obtained a state permit but the Army Corps balked, saying the property had wetlands within the Lake St. Clair drainage system even though they were separated from a tributary ditch by a man-made earthen berm.